142 Dr. Meyen’s Researches in Physiological Botany. 
this is very improbable; for it was shown at length in the 
former Report, that it is exactly these secondary layers, which 
by boiling with an alkali, &c., are converted into a starch-like 
substance; besides, the microscope should have been used be- 
fore those analyses were made, but such observations are not 
mentioned. 
In the meeting of the Parisian Academy on the 14th of Ja- 
nuary, M. Payen read a paper, entitled “ Mémoire sur les ap- 
plications théoretiques et pratiques des propriétés du tissu 
élémentaire des Végétaux*,” the contents of which are of con- 
siderable interest, but would here lead us too far into the pro- 
vince of Chemistry. 
On the 4th of February, 1839, new researches were made 
public by M. Payen; he gave the composition of the incrust- 
ing matter of wood as C*> H* QO, while the formula for the 
primitive cellular membrane is C** H% O'° or C* H's O? 
+H?O. In the sitting of the Academy of the 30th of July, 
a new treatise by M. Payen was read, “On the tissue of 
Plants and on the incrusting substance of Woodf,” an extract 
from which has been published by the author. M. Payen re- 
marks, that he had already made known to the Academy his 
researches, according to which all young parts of plants con- 
tain a considerable portion of substances containing nitrogen; 
that moreover the peculiar substance of the membranes in 
different plants has always the same composition ; and that in 
those parts which are grown woody by age, there are con- 
tained two chemically different substances, viz. the primitive 
membrane and the hard incrustation. 
“‘ Many tissues,” observes M. Payen, “ acquire a high degree 
of hardness without possessing large quantities of incrusting 
matter.” (In the same manner we may bring forward cases 
where many cells with thickened sides have no hardness, and 
it is evident from this that the hardness of the vegetable sub- 
stance does not depend solely on the thickening of the walls 
of the cells, but on the chemical change in the layers of cel- 
lular membrane, M.) The latest analyses and microscopical 
observations of M. Payen have led him to conclude that wood 
consists of not less than four different substances, viz. the pri- 
mitive cellular membrane, and the sclérogéne, which again is 
said to consist of three peculiar matters; the one insoluble in 
water, alcohol, and ether, the other soluble in alcohol, and 
the third in all three solvents. The ultimate composition of 
these four substances in the above order is as follows :— 
* Comptes Rendus de 14 Janv. 1839, p. 59. 
+ Ibid. 20 Juill. 1839, p. 149. 
